Boost was originally an effect in which the arrows increased their speed when the arrows came near the key pressing zone. This was to give hyperspeed an additional boost for those users who felt it needed it. Although in version .803 it appears that boost was scrapped of its original purpose and is generally another hyperspeed setting, as the original hyperspeed setting now cannot be used when attempting to use boost. So, in short, if you use boost it is the equivalent now of using hyperspeed, but only with more oddball speeds for those who aern't quite ready to move up an entire rung on the hyperspeed settings yet.

Additional visual modifiers to make the game more difficult (and interesting).

Dizzy: An effect where the "Up" and "Down" arrows, as well as the "Left" and "Right" arrows appear to swap directions with one another. The up arrow will come up as down, the left arrow will come up as right, and so on. This effect messes with those who focus on the actual arrow instead of it's position on the chart in order to hit it correctly. This would probably trip up beginner single handed players the most, as using the arrow key settings with one hand deals with focusing on direction of the arrows, in contrast to where your fingers are on the arrow key pad.

Tornado: An effect where the arrows appear to be blown upward to the right, and swoop to the left back to the arrow key pressing positions. This effect affects those that are hitting the arrows by position on the chart, and not the direction the arrows face. Even experienced players can have serious difficulty attempting to play using this effect.

Mini: An effect where both the arrows and the key pressing area become very small (in the newer versions), while in the older versions, only the arrows got smaller, while the key pressing area stayed the same size. This usually doesn't effect much in terms of trying to play a song, unless the songs get into "for guru's only" or higher difficulties where arrows are very close together and need to be seen properly to hit. Mini is more of a PA handicap, as it is more difficult to hit perfects while playing on mini.

Hidden: Shows arrows completely until they reach the key press area. Once there, the arrows disappear from view, and you have to guess when to hit to obtain an average, good, or perfect. This effect is easier to play on than most would expect, as they disappear at the same frame every time, so you can usually hit them all as perfect or good without much effort.

Sudden: The inverse of hidden, only shows arrows when they reach the arrow key pressing area. This is a very difficult setting to play on, unless you are able to memorize a song's arrows. Being able to get a good PA using this setting on harder songs is nearly impossible.

Stealth: Never shows the arrows at any point. A song played on this setting must be memorized or luckily mashed in order to pass.

Blink: The arrows toggle on and off, approximately two times from the bottom of the screen to the top of the screen, between visible and hidden. This effect, although not as bad as sudden or hidden, can become confusing when playing harder songs where arrows are very close together, where blinking can seriously mess up your ability to hit the arrows properly.

AutoFail enables players to set the game to automatically fail when the optional conditions are set. These conditions consist of how many of each type of rating received (perfect, boo, miss, etc.) and the number of them are set by the player. The reason you would want to use AutoFail is if you were attempting to go for a AAA or a skill token that required that a certain amount of a type of rating not be reached.